Amazon CloudFront announces reduced billing granularity for Lambda@Edge function duration from 50ms down to 1ms. This will lower the price for most Lambda@Edge functions, more so for functions of short duration. Now, compute duration will be billed in 1ms increments per invocation instead of being rounded up to the nearest 50ms increment per invocation as before.
Lightweight functions such as header manipulations or URL rewrites tend to have a short duration. With this change, it will now be even more cost effective to run these functions on Lambda@Edge. For example, a function that runs in 10ms on average used to be billed for 50ms. Now, that function will be billed for 10ms resulting in a 80% reduction in duration spend. This change applies to all four Lambda@Edge event triggers – viewer request, viewer response, origin request and origin response. This change will be effective starting April 1, 2021. For more information, visit the CloudFront Pricing Page.